1. Field of the Invention
The present invention relates to a laminated inductor.
2. Description of the Related Art
One conventionally known method to manufacture a laminated inductor is to print internal conductor patterns on ceramic green sheets containing ferrite, etc., and then stack these sheets to be sintered.
Under a representative manufacturing method for laminated inductor, through holes are formed at specified locations on ceramic green sheets made from ferrite powder. Next, a conductive paste is used to print coil conductor patterns (internal conductor patterns) on one primary side of each sheet having through holes formed on it, so that when the sheets are stacked, the through holes will be connected together and spiral coils will be formed as a result.
Next, the sheets having through holes and coil conductor patterns formed on them are stacked according to a specified configuration, with a ceramic green sheet (dummy sheet) having no through holes or coil conductor patterns stacked at the top and also at the bottom. Next, the obtained stack is pressure-bonded and then sintered, after which external electrodes are formed on the end faces onto which the ends of coils are led out, to obtain a laminated inductor.
There has been a demand for laminated inductors supporting large current (higher rated current) in recent years. According to Patent Literature 1, for example, switching the magnetic material from conventional ferrite to soft magnetic alloy is being studied in order to meet this demand. Soft magnetic alloys proposed for this purpose, such as Fe—Cr—Si alloy and Fe—Al—Si alloy, have a higher saturated magnetic flux density than that of ferrite. On the other hand, these materials have a much lower volume resistivity compared to that of conventional ferrite.